Conventionally, as described in JP-A-2000-121547, a detection cell as a detecting cell for detecting a component and/or a concentration of the component in liquid sample with using light is well known.
The detection cell includes two glass plates as two substrates, which are stacked. Further, the cell includes a fluid passage as a pathway for flowing the liquid sample. The fluid passage is formed between one surface of one glass plate and a facing surface of the other glass plate.
Here, the liquid such as gasoline, water, alcohol such as ethanol and acetic acid has absorption wavelength in mid-infrared zone between three micrometers and ten micrometers. Thus, with using the detection cell described in JP-A-2000-121547, a liquid component sensor with using infrared light is provided. Thus, the sensor detects the component and/or the concentration of the component in liquid.
However, when the detection cell is used as the component sensor, the liquid component sensor necessarily includes an infrared light source for irradiating the infrared light, a filter for passing the infrared light having a predetermined wavelength therethrough (i.e., the filter filtering the infrared light selectively in the wavelength, a spectrometer for executing spectrum analysis of light penetrated through the detection cell (i.e., the spectrometer dispersing light), and a light detector for detecting dispersed light in addition to the detection cell. Further, it is necessary to arrange the filter, the detection cell and the spectrometer between the infrared light source and the light detector with high accuracy in position. Accordingly, the number of elements in the sensor is large, and the detection accuracy may be reduced if the position of each element is deviated from a proper position.